AUGUSTA – A union claiming 10,000 members is backing Democratic Rep. Tom Allen in his bid to unseat Republican Sen. Susan Collins.

The announcement Tuesday by the Maine State Employees Association, Local 1989 of the Service Employees International Union, cited the six-term 1st District congressman’s record on health care, prescription drugs, fiscal responsibility and civil rights.

The union said questionnaires were sent to both candidates but that only Allen completed his.

Collins is seeking a third Senate term.

“Tom Allen is a tireless advocate for workers and retired workers in Maine and across the nation,” Paul Gilbert, a retired member of MSEA-SEIU from Jay and chairman of the union’s Political Action by Service Employees and Retirees Committee, said in a statement distributed Tuesday.

“Tom Allen will protect and strengthen domestic priorities like Social Security and Medicare. We can count on Tom Allen to show the leadership necessary in the U.S. Senate to make prescription drugs more affordable,” Gilbert said.

A spokeswoman for the Republican incumbent said Tuesday the SEIU nationally was affiliated with a group that had mounted “attack ads” against Collins.

“We didn’t think there was an opportunity to get that endorsement,” said Elissa Davidson of the Collins campaign.

In September, Americans Against Escalation in Iraq announced an ad campaign against Republican Sens. Mitch McConnell of Kentucky, Norm Coleman of Minnesota, Pete Domenici of New Mexico and Collins for what the advocacy group said was their continued support of the Bush administration’s Iraq war policy.

The same group had sought to put the spotlight on Collins several times before.

Americans Against Escalation in Iraq describes itself as a coalition of groups including SEIU, MoveOn.org Political Action and Americans United for Change.

The Maine State Employees Association, SEIU Local 1989, says it represents workers in all three branches of state government, the Maine Maritime Academy, Maine Community College System, Maine Military Authority, the Maine Public Employees Retirement System, the city of Lewiston, York County government, Waldo County government, Child Development Services, Home Care for Maine, Alpha One and the American Red Cross in Bangor.

MSEA-SEIU also represents workers at two specialized health care facilities: the Green Valley Association in Patten and Treats Falls in Orono.

“Tom Allen will balance the federal budget to prevent more costs from being pushed onto our children and grandchildren. He’ll make sure that future appointees to the U.S. Supreme Court respect the rights of all Americans. And he believes in the right of workers to organize as union members,” Gilbert said in the union endorsement statement.

Davidson noted that Collins, who served in Republican Gov. John McKernan’s Cabinet, had been a state worker herself and had enjoyed support from rank-and-file state employees.